1. Field of the Invention
The present invention deals with the field of devices for controlling boat lift apparatus. Boat lift apparatus is used normally adjacent large bodies of water for removing a boat or other watercraft from the water to an elevated position for storage. This is normally controlled by a cable mechanism attached to the boat lift apparatus.
This boat lift cable must be accurately controlled for movement and the present invention provides a double reduction gear drive for powering movement of such boat lifting cables which is significantly improved since it utilizes direct engagement of gearing rather than chains or pulleys or other remote means for connecting rotating shafts. Also the mutual orientation of the axis of the input shaft, the internal shaft, the output shaft and the winding spool provide a distinct improvement over the prior art since lubrication is significantly enhanced and smaller sized designs can be utilized. The maintenance requirements for chain and belt drive systems is problematic in the relatively harsh environments that are normally experienced at the locations where such boat lifts are utilized. For this reason the use of a direct drive double reduction gear mechanism is a significant enhancement over the prior art.
2. Description of the Prior Art
Various prior art devices have been utilized for the purposes of controlling movement of boat lifting mechanisms such as shown in U.S. Pat. No. 3,191,389 patented Jun. 29, 1965 to J. B. Poe on a xe2x80x9cBoat Liftxe2x80x9d; and U.S. Pat. No. 3,265,024 patented Aug. 9, 1966 to C. W. Kramlich on a xe2x80x9cBoat Liftxe2x80x9d; and U.S. Pat. No. 3,504,502 patented Apr. 7, 1970 to L. H. Blount on a xe2x80x9cLift Dock For A Water Borne Vesselxe2x80x9d; and U.S. Pat. No. 3,675,258 patented Jul. 11, 1972 to Bradley M. Osmundson on a xe2x80x9cBoat Hoistxe2x80x9d; and U.S. Pat. No. 3,778,855 patented Dec. 18, 1973 to Nikolai Kariagin et al and assigned to Whittaker Corporation on a xe2x80x9cTelescopic Gravity Davitxe2x80x9d; and U.S. Pat. No. 3,791,229 patented Feb. 12, 1974 to Heinz Litezki and assigned to Schiess Aktiengesellschaft on a xe2x80x9cLifting Device For Lifting And Lowering Heavy Loadsxe2x80x9d; and U.S. Pat. No. 4,337,868 patented Jul. 6, 1982 to Narahari Gattu and assigned to Harnischfeger Corporation on a xe2x80x9cTelescopic Crane Boom Having Rotatable Extend/Retract Screwsxe2x80x9d; and U.S. Pat. No. 4,589,800 patented May 20, 1986 to Charles L. Nasby, Jr. on a xe2x80x9cDock Structure And Method And Apparatus For Raising And Lowering Samexe2x80x9d; and U.S. Pat. No. 4,641,996 patented Feb. 10, 1987 to Morton Seal on a xe2x80x9cSide Loading Boat Liftsxe2x80x9d; and U.S. Pat. No. 4,686,920 patented Aug. 18, 1987 to James L. Thomas on a xe2x80x9cCradle Type Boat Liftsxe2x80x9d; and U.S. Pat. No. 4,954,011 patented Sep. 4, 1990 to Samuel H. Stenson on a xe2x80x9cPowered Method And Apparatus For Lifting A Boatxe2x80x9d; and U.S. Pat. No. 4,983,067 patented Jan. 8, 1991 to David M. Montgomery on a xe2x80x9cBoat Lift Apparatusxe2x80x9d; and U.S. Pat. No. 5,020,463 patented Jun. 4, 1991 to Robert E. Franklin et al on an xe2x80x9cArrangement For Raising Or Lowering Boats Or The Likexe2x80x9d; and U.S. Pat. No. 5,051,027 patented Sep. 24, 1991 to George F. Horton on a xe2x80x9cBoat Liftxe2x80x9d; and U.S. Pat. No. 5,090,842 patented Feb. 25, 1992 to David M. Montgomery on a xe2x80x9cBoat Lift Apparatus And Systemxe2x80x9d; and U.S. Pat. No. 5,140,923 patented Aug. 25, 1992 to Kevin L. Wood on a xe2x80x9cRaising And Lowering Devicexe2x80x9d; and U.S. Pat. No. 5,211,124 patented May 18, 1993 to John N. Reiser and assigned to Triton Corporation on a xe2x80x9cWinch Construction For Boat Liftxe2x80x9d; and U.S. Pat. No. 5,261,347 patented Nov. 16, 1993 to Peter W. Mansfield on a xe2x80x9cSailboat Davitxe2x80x9d; and U.S. Pat. No. 5,287,821 patented Feb. 22, 1994 to Byron L. Godbersen on an xe2x80x9cElectric Drive Mechanism For Boat Hoist Winchxe2x80x9d; and U.S. Pat. No. 5,390,616 patented Feb. 21, 1995 to Henry Roth on a xe2x80x9cDock Mounted Small Boat Lifting Systemxe2x80x9d; and U.S. Pat. No. 5,593,247 patented Jan. 14, 1997 to James A. Endres et al and assigned to Endcor Inc. on a xe2x80x9cProgrammable Boat Lift Control Systemxe2x80x9d; and U.S. Pat. No. 5,687,663 patented Nov. 18, 1997 to Noel D. Wahlstrand on a xe2x80x9cBoat Lift Transport Apparatusxe2x80x9d; and U.S. Pat. No. 5,701,834 patented to Richard A. Lyons on Dec. 30, 1997 on a xe2x80x9cLift For Watercraftxe2x80x9d; and U.S. Pat. No. 5,755,529 patented May 26, 1998 to R. R. Brad Follett on a xe2x80x9cBoat Liftxe2x80x9d; and U.S. Pat. No. 5,769,568 patented Jun. 23, 1998 to David G. Parkins et al and assigned to ABL Boat Lifts on an xe2x80x9cAdaptable Boat Liftxe2x80x9d; and U.S. Pat. No. 5,772,360 patented Jun. 30, 1998 to Donald M. Wood, II on a xe2x80x9cTopless Watercraft Lifting Apparatus With A Differential Gearing Systemxe2x80x9d; and U.S. Pat. No. 5,803,003 patented Sep. 8, 1998 to Robert V. Vickers and assigned to The Louis Berkman Company on a xe2x80x9cRotary Boat Liftxe2x80x9d; and U.S. Pat. No. 5,915,877 patented to Charles L. Sargent et al on Jun. 29, 1999 and assigned to Quality Boat Lift, Inc. on a xe2x80x9cPositive Drive Boat Liftxe2x80x9d; and U.S. Pat. No. 5,934,826 patented Aug. 10, 1999 to Peter W. Mansfield on a xe2x80x9cBoat Lift Apparatusxe2x80x9d; and U.S. Pat. No. 5,947,639 patented Sep. 7, 1999 to Richard B. Bishop et al on a xe2x80x9cBoat Lift Apparatusxe2x80x9d; and U.S. Pat. No. 5,957,623 patented to Charles L. Sargent et al on Sep. 28, 1999 and assigned to Quality Boat Lifts Inc. on an xe2x80x9cElectrically Insulated Positive Drive Boat Liftxe2x80x9d; and U.S. Pat. No. 5,988,941 patented Nov. 23, 1999 to Charles L. Sargent et al and assigned to Quality Boat Lifts, Inc. on a xe2x80x9cBoat Lift Cable Lock Apparatusxe2x80x9d; and U.S. Pat. No. 6,006,687 patented Dec. 28, 1999 to Jeffrey M. Hillman et al and assigned to Marine Floats, Inc. on a xe2x80x9cModular Floating Boat Liftxe2x80x9d; and U.S. Pat. No. 6,033,148 patented Mar. 7, 2000 to Lynn P. Norfolk et al and assigned to Norfolk Fabrication, Inc. on a xe2x80x9cHousing For A Boat Lift Motor, Pulley And Gear Drivexe2x80x9d; and U.S. Pat. No. 6,122,692 patented Feb. 8, 2000 to Lynn P. Norfolk et al and assigned to Norfolk Fabrication, Inc. on a xe2x80x9cHousing For A Boat Lift Motor Pulley And Gear Drivexe2x80x9d and U.S. Pat. No. 6,122,994 patented Sep. 26, 2000 to Lynn P. Norfolk et al and assigned to Norfolk Fabrication, Inc. on a xe2x80x9cHousing For A Boat Lift Motor, Pulley And Gear Drivexe2x80x9d; and United States Design Patent No. Des. 390,188 patented Feb. 3, 1998 to Lynn P. Norfolk et al and assigned to Norfolk Fabrication, Inc. on a xe2x80x9cBoat Lift Motor And Gear Housingxe2x80x9d.
The present invention provides a double reduction gear drive device for powering movement of a boat lifting cable which includes a main housing defining a main housing chamber therein. The main housing also preferably defines an input aperture and an output aperture therein both in fluid flow communication with respect to the main housing chamber.
An input shaft is also included rotatably mounted with_respect to the main housing and extending through the input aperture into the main housing chamber. A primary input shaft bearing is also included mounted in the main housing immediately adjacent the input aperture. This primary input shaft bearing is adapted to receive the input shaft extending therethrough to facilitate rotational movement thereof relative to the main housing.
A secondary input shaft bearing may also be included mounted in the housing spatially disposed from the primary input shaft bearing and adapted to receive the input shaft therethrough in order_to facilitate rotational movement thereof relative to the main housing.
An input gear is also preferably included secured to the input shaft at a position within the main housing chamber. An internal shaft is rotatably movably mounted within the main housing chamber of the main housing in a position extending approximately parallel to the input shaft and slightly displaced laterally therefrom. This input shaft and the internal shaft are both oriented in a generally vertically plane parallel with respect to one another.
A main internal gear may be also included secured on the internal shaft to be rotatable therewith. This main internal gear is preferably in engagement with respect to the input gear in such a manner as to be rotatably driven responsive to rotation of the input gear. The main internal gear is preferably larger than the input gear in order to cause the internal shaft to rotate at a rotational speed less than the rotational speed of the input shaft. A first internal shaft bearing may also be mounted within the main housing in such a manner as to receive the internal shaft extending therethrough to facilitate rotational movement thereof relative to the main housing. Similarly a second internal shaft bearing may be mounted within the main housing spatially disposed from the first internal shaft bearing. It is adapted to receive the internal shaft extending therethrough to facilitate rotation thereof relative to the main housing.
A worm gear is also preferably included secured on the internal shaft for rotation therewith. This worm gear is positioned at an intermediate position on the internal shaft spatially disposed from the main internal gear.
A main bearing journal is also preferably fixedly mounted within the main housing chamber. Preferably the second input shaft bearing and the first internal shaft bearing are both mounted in the main bearing journal and maintained thereby spatially disposed from one another to maintain fixed positioning thereof relative to the main housing.
An output shaft is also movably mounted within the main housing chamber of the main housing to be rotatable with respect thereto. The output shaft is positioned to also extend outwardly through the output aperture. The output shaft and the internal shaft are preferably oriented in a generally vertically extending plane and are oriented approximately perpendicular with respect to one another. The output shaft is partially positioned within the main housing and extends outwardly therefrom through the output aperture. A first output shaft bearing and a second output shaft bearing are also mounted within the main housing spatially disposed from one another and adapted to receive the output shaft extending therethrough to facilitate rotational movement thereof relative to the main housing.
An output gear is secured to the output shaft to be rotatable therewith and is positioned in engagement with respect to the worm gear to move therewith. The output gear is preferably larger than the worm gear to cause the output shaft to rotate at a rotational speed less than the rotational speed of the internal shaft.
A boat lifting cable spool is attached to the output shaft outside of the main housing chamber and is rotatable therewith to control winding of one or more boat lifting cables thereon. The boat lifting cable spool extends generally horizontally preferably and approximately perpendicular with respect to the internal shaft and the input shaft.
A drive means is operatively coupled with respect to the input shaft to selectively drive it. In this manner it will cause rotation of the boat lifting cable spool with enhanced torque and lower rotational velocity than the drive means itself in order to control movement of the boat lifting cable. The drive means preferably includes a drive shaft extending outwardly therefrom and being rotationally driven therewith. The drive shaft is coupled to the input shaft for selectively causing rotation thereof.
A boat lifting cable can also be included in a position secured to the boat lifting cable spool for controlling winding thereof on the spool. Two such boat lifting cables are normally utilized spaced apart on the spool.
A coupling means may also be attached to the drive shaft and the input shaft in order to cause simultaneous and similar movement therebetween. The coupling means preferably includes a key means positioned between the first drive shaft and the coupling means for securing them to one another. Another keying means is included positioned between the input shaft and the coupling for selectively securing them with respect to one another.
A coupling housing may also be included extending around the coupling itself. This coupling housing will preferably define a coupling chamber therein and a coupling input aperture and outlet aperture. The coupling housing is preferably securable with respect to the drive with the drive shaft thereof extending into the coupling through the coupling input aperture. The coupling also is preferably securable with respect to the main housing with the coupling aperture positioned in registration with respect to the main housing input aperture and with the input shaft extending through the coupling output aperture into the coupling chamber to a position adjacent the drive shaft. The coupling is preferably rotatably movable with respect to the coupling chamber and is secured to the drive shaft and input shaft to cause similar rotational movement. The coupling housing also includes a coupling bearing mounted therein immediately adjacent the coupling output aperture which is adapted to receive the input shaft therethrough to facilitate rotation thereof relative to the coupling housing.
The main housing of the present invention may include an enlarged wall section adjacent the first output shaft bearing in order to facilitate placement and lubrication thereof. Also the output gear may actually be configured as a helical flange gear as shown best in FIGS. 1 and 2 to facilitate engagement thereof with respect to the worm gear. Also the worm gear itself is preferably constructed with the teeth thereof having a lead angle of less than 7 degrees and 30 minutes in order to avoid backdriving thereof and enhance self-locking characteristics.
It is important to appreciate that the present invention is positionable with the two gear reduction mechanisms within a single housing. However, it is also contemplated within the scope of the present invention that the gear reduction mechanisms can each be positioned within their own housing. In this case the main overall housing can be defined as the composite of the two housings wherein the first step of gear reduction occurs in the first housing member and the second step of gear reduction occurs in the second housing member. This could be easily achieved merely by defining two separate housing members which comprise the overall housing itself with one set of reduction gears located in one housing and the second set of reduction gears located in a second immediately adjacent housing.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein two steps of gear reduction are achieved with two sets of reducing gears in direct engagement with respect to one another thereby eliminating the need for any chain or belt operatively interconnecting the rotating shafts of the reduction means.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein controlled operation of a boat lift is achieved.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein a horizontally extending boat cable spool is operatively controlled for achieving full functionality of a boat lift.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein lubrication is significantly enhanced.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein two pairs of reduction gears are included which may be positioned within the same housing or may be separated and positioned within adjacent housings.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein all reduction gearing is achieved by direct interconnection of gear teeth rather than use of any indirect connection such as chains and sprockets or V-belts and pulleys.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein maintenance requirements are minimized.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein parts replacement is greatly facilitated.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein a drive means is connected through a direct drive to the boat lifting cable winding spool.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein self-locking and anti backdriving is achieved by utilizing a worm gear with a lead angle of less than 7 degrees and 30 minutes.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein no exposed mechanical parts extend outside of the housing means.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein a one-piece gear housing can be utilized.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein a compact low profile design provides an aesthetically pleasing external appearance.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein capacities from 4500 lbs. to 120,000 lbs. are achievable.
It is object of the present invention to provide a double reduction gear drive mechanism for powering movement of boat lifting cables wherein the housing can be sealed to provide a totally maintenance free environment under certain conditions.